


An Unexpected Lesson

by thewinchesterlifestyle



Series: John's Lessons [1]
Category: Supernatural
Genre: Age Difference, Barebacking, Biting, Bottom Castiel, Cheating, Dirty Talk, Exhibitionism, Fingering, Implied Top Dean, M/M, Name-Calling, Rough Sex, Size Difference, Size Kink, Teen Castiel, Teen Dean, Top John, Voyeurism, dubcon, teaching sex
Language: English
Status: Completed
Published: 2016-12-05
Updated: 2016-12-05
Packaged: 2018-09-06 18:46:47
Rating: Not Rated
Warnings: Underage
Chapters: 1
Words: 1,704
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8764750
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: Dean and Castiel are fumbling around trying to have sex for the first time when John walks in on them.





	

**Author's Note:**

> Tagged underage because states/countries age of consent vary.
> 
>  
> 
> Because I was asked and there was a specification on this one: John is 42.

Castiel winced when Dean pushed a third finger in too soon without adding any additional lube. He tried to relax on the bed but at this point both of them were fumbling more than anything. It had been a spur of the moment thing that Castiel was now questioning. Dean’s fingers pushed against his insides, stretching him, as he spread his legs a little wider.

He sighed when Dean reached up and stroked at his cock. The pleasure had him relaxing better into the sheets and his grip on them lessened as his softening cock started to harden once more.

Castiel was so focused on keeping himself relaxed and listening to Dean’s soft words that he didn’t hear the front door. Neither of them had heard it and it wasn’t until John Winchester was pulling Dean away that Castiel even realized something was off. It had embarrassment heating his cheeks and his cock softened at his mortification.

“That was one of the most pathetic displays I’ve seen.” John’s voice was gruff as Castiel blinked at him in surprise. Dean was also gaping at his father and when John started to remove his pants Castiel could see a protest climbing up Dean’s throat but it died at one look. “This is how you fuck like a man.”

The sight of Dean’s father standing naked before him, eyes roving over his own naked body, had Castiel’s hands flying up to cover himself in automatic instinct. He shivered as John moved towards him in an almost predatory way that had something in his gut tightening.

Castiel was still laying there with his legs spread, completely naked and exposed, as John moved between this legs. Still shocked he glanced down and took in the sight of a truly impressive cock. It was long and thick, hard and curving slightly to the left.

He swallowed roughly. There was no way that _thing_ could possibly fit when three of Dean’s fingers had hurt.

“Dad—” Dean took a step forward the same time John yanked Castiel closer and gripping his cock Castiel felt it press against his hole after the older man had stroked himself with a lube slick palm. Castiel knew his hole was in no way prepared enough for that monster to be inside but that didn’t slow John Winchester down.

Everything seemed to slow down and then John, Dean’s  _father_ , was pushing his enormous cock inside. “Oh.” Castiel’s eyes screwed shut and his mouth dropped open at the stretch. It burned enough to bring tears to his eyes but he felt  _full_  and it reminded him of the time he’d first pushed a slim dildo inside himself if only he could push past the undeniable pain such an intrusion was causing.

His large hands gripped onto Castiel’s body and Castiel struggled not to sob out at the way his ass was spread impossibly wide open. John kept pressing forward with occasional short thrusts until he was completely buried inside and Castiel gasped. His hole clenched and unclenched without his control, his soft cock rested between them and the painful stretch had him struggling to pull in shuddering breaths. 

“If you’re doing it  _right_  you should actually get a moan instead of him lying there while you clumsily push your fingers inside. Right now his tight little hole is trying to get used to what it feels like to have a real man’s dick inside of his slutty ass.” Castiel could see John looking over at his son but Dean wasn’t saying a single word. “When you have such a plump ass to stick your dick in you should at least know what you’re doing so you’re not wasting it.”

Instead Dean stood there staring at them but Castiel didn’t have long to think about it before John was rolling his hips back and snapping them forward in a hard motion that had him moving on the bed. The thrust had nailed his prostate and Castiel moaned his approval even as the pleasure mixed with the ever-present pain of a hole stretched too far too soon.

Castiel dug his heels into the backs of John’s thighs and shoved his head back when John started to fuck him. It started off with a slow, even pace that was driving him insane and each time John got his prostate Castiel’s fingers dug tighter into him as the pain slowly started to be replaced by pleasure. “Fuck oh fuck ohhhh.” His ass was clenching around John’s cock and he barely heard John’s words.

 _This_  was what he’d imagined when he’d thought of fucking.

“See, Dean? See how his ass is trying to pull me in further? How he’s gripping me and moaning like a pretty little whore?  _That’s_  how it should look when you’re fucking.” Castiel’s fingers moved and scratched down John’s back as he pushed into John’s thrusts trying to encourage him. “If you come closer you can see how taut his hole is around my dick. When I’m done he’ll be gaping and puffy. You’re not near as big so when you finally figure out what you’re doing his hole isn’t going to be near as ruined.”

John’s body ended up draping over him, pinning him harder to the mattress and the long strokes turned into a rougher rutting that was sending more bursts of pleasure flying through him. Castiel could feel where his own hard cock was trapped between them and raked his fingers once more down John’s back. “ _Harder_.” He was lost to pleasure and at this point Castiel just wanted to get off. If Dean wasn’t going to even attempt to stop his father then Castiel was going to enjoy that wonderful, massive cock pounding into him. “Fuck harder please oh oh oh yes there yesss—I…oh  _fuck ohhhhhh_.”

John’s chest rumbled against him when he spoke to Dean but Castiel was too busy shoving his face against John. He bit and dug his fingers in, legs tightening and ass clenching.

This was far better than the times he’d gotten himself off. He might have to get a bigger dildo because once he got past the pain being this full was amazing.

“Oh so close yes please… _Mr. Winchester oh fuck oh fuck yes yes yes_.” John’s pace was much harder and quicker, the sounds of his grunts and groans reached Castiel but they sounded like they were at a distant. He was on the edge, so very very close, until John drew back just enough to close a hand around his cock.

Castiel’s toes curled and his mouth dropped open as he came with a wail all over John’s hands. The entire time John kept snapping his hips forward in a hard, unrelenting pace. “Look at that, Dean. Look how debauched he looks. How sated. That’s what a well fucked whore looks like when you’re finished if you’ve done it right.”

He felt warm and dazed, eyes hooded and cheeks flushed, as each thrust from John into his sensitive body had whimpers escaping at the feeling of too much. “Oh oh ohhhh.” His eyes rolled and the only sounds he could hear was John and the groan of the mattress under John’s increasingly harsh movement.

The headboard had started banging against the wall as John started practically slamming into him.

Balls slapped against him and that wonderful, thick cock kept pumping into his hole until John shoved deep and came with a pleasured moan. Castiel lazily watched the way the older man’s eyes closed and his face showed his obvious pleasure.

“See how he had wrapped his legs around me? That will help you get deeper.” He drew out and Castiel found himself being rolled over as he hissed lowly in pain at the feeling of John’s softening cock slipping from his aching ass. “Look, Dean.” Fingers hooked on his puffy rim and Castiel whined lowly but stayed there on his belly unable to do much of anything. “That’s what a well fucked hole looks like. See how ruined he is?”

John’s fingers pulled away and Castiel could feel him shifting off the bed. The room was silent save for the sounds of him dressing and Castiel couldn’t look at Dean. His body still felt warm and he felt like he  _had_  been well fucked.

He slowly moved off the bed and tried to ignore the way his ass ached pleasantly while John’s release slowly started to leak out of his gaping hole. His eyes flicked up and he took in Dean’s expression. There was something glazed there and he glanced away.

A large hand landed on his shoulder but John wasn’t addressing him, “Next time I’ll give you a more thorough lesson in how to properly fuck a tight ass. Hopefully this was a learning experience, Dean and you won’t be fumbling around back there without a clue.”

Castiel’s face was flushed with shame as the realization that he’d let his boyfriend’s forty-something old father fuck his ass right in front of his boyfriend. And he’d moaned just like the whore John had called him several times.

His ass clenched up again and a low sound escaped. It hurt. Kind of a good hurt but Castiel knew he’d be feeling that fucking for quite awhile. John certainly hadn’t been easy on him even though he’d, possibly knowingly, took Castiel’s virginity without thought.

“If my boy ever figures out how to use you properly he’ll be in for a treat.” Now John was looking at him and Castiel flushed even darker, “That ass of yours felt amazing not to mention the sounds you were making. I’ll look forward to showing both of you boys the proper way to fuck.”

Then he was gone and Castiel couldn’t look at Dean even if he wanted to. Instead he limped towards the bathroom, leaking and sore, before shutting the door and looking at the shower. He needed to clean up the mess and gather some small amount of courage to be able to look Dean in the face after that.

Not to mention he needed to find out why the fuck Dean hadn’t even voiced a single protest before, during and after his own father fucked his boyfriend.

**Author's Note:**

> I did a poll awhile back and saw how popular John/Cas was so I figured this one might be something you all would enjoy (though I know there was a higher number who seemed to love John/Dean so I might see about that soon)!
> 
>    
> Please leave a comment and let me know what you thought. Remember comments are motivation for continuing to write and post fanfics!


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